The ornamental design for a multichambered whistle, as shown and described.
FIG. 1 is a right side top perspective view of the multi chambered whistle.
FIG. 2 is a left side front perspective view of the multi chambered whistle.
FIG. 3 is a right side bottom perspective view of the multi chambered whistle.
FIG. 4 is a front end plan view of the multi chambered whistle.
FIG. 5 is a top plan view of the multi chambered whistle.
FIG. 6 is a bottom plan view of the multi chambered whistle.
FIG. 7 is a right side plan view of the multi chambered whistle; and,
FIG. 8 is a left side plan view of the multi chambered whistle.
The drawings show both wire frame contour lines and surface shading lines. It is understood that all of the continuous solid lines in the drawings represent wire frame contour lines.